Device for supervising the ink supply of a printing press



B. WIRZ May 6, 1969 3,442,121 DEVICE FOR SUPERVISING THE INK SUPPLY OF A PRINTING PRESS Sheet Filed Dec. 27, 1965 I Inventor: um H QloT Wutz BY Ham QTY o1 neYs May 6, 1969 B. WIRZ 3,442,121 DEVICE FOR SUPERVISING THE INK SUPPLYOF A PRINTING PRESS Filed Dec. 27, 1965 Z of 4' Sheet Inventor: EUGKHQIQT Wm BY RQMMAWL y 6, 1959- B. wmz 3,442,121

DEVICE FOR SUPERVISING THE INK SUPPLY OF A PRINTING PRESS Filed D90. 27. 1965 Sheet 3 of 4 Inventor: Em: KHQRD" h R1;-

BY N

TTOQNEYS May 6, 1969 B. WIRZ DEVICE FOR SUPERVISING THE INK SUPPLY OF A PRINTINGPRESS Sheet 4 of 4 Filed Dec, 27, 1965 In venfar: BURKHHRD'T W ya;

Q'rx oaneYs United States Patent US. Cl. 73-150 5 Claims ABSTRACT OF THE DISCLOSURE A device for measuring the pulling power of printing inks in which two rotatable measuring rollers with a nonelastic surface engage a non-elastic inking mechanism roller of a printing press. One of the measuring rollers is mounted radially resilient in reference to the inking mechanism roller and the other is mounted tangentially resilient in reference to the inking mechanism roller. Electric measuring means which are responsive to movements of the measuring rollers in radial and tangential direction respectively, as caused by the pulling power of the ink to be supervised, generate signals corresponding to the movements of the measuring rollers and these signals are used to control means for computing the pulling power of the printing inks.

The present invention relates to a device for supervising the ink pulling power of printers ink as used for lithographic printing presses and more particularly, to a device for supervising the ink pulling power On an inker roller of a printing press. The term ink pulling power as used herein refers to the tackiness of the ink and is a term generally understood and used in the printing industry.

The present application is a continuation-in-part application based upon my co-pending application Ser. No. 471,660 filed July 13, 1965, now Patent No. 3,368,399 issued Feb. 13, 1968.

It is 'well understood that a high printing quality by offset printing can be obtained only when the ink supply and the water supply are substantially continuously supervised and adjusted in reference to each other. Such control is necessary for the starting period of the press, that is, the initial period of operation until the water supply and the ink supply have reached a state of equilibrium and also for the continuing printing operation during which an offset printer must continuously control the ratio of the water supply and the ink supply. Due to the mutual coaction of ink and water, the starting period, that is, the period during which the ink and the water are adjusted so that the density of the ink remains substantially constant on the sheets on which printing is to be effected, may be a very prolonged one if the adjustment is not expertly efiected. As stated before, the printing operation itself, following the completion of the starting period, also requires a careful and continuous supervision of the ink water relationship as otherwise ink fluctuations and thus quality variations of the printed sheets may exceed commercially and practically acceptable tolerances, especially for multi-color wet-in-wet printing. Control of the ink water relationship is particularly difficult when printing is to be effected on substantially non-absorptive material, as obviously, material of this kind makes it difficult to control the water supply.

The relationship of ink and 'water in lithographic printing is determined by three principal factors, to wit, the amount of the water present on the printing plate, the thickness of the ink layer on the spreaders or ink applying rollers of the press and the pulling power of the ink.

The ink pulling power affects the ink distribution and thus the reproduction of the tone values of the printing. Generally, a good tone value reproduction can be obtained only with an ink which is only slightly emulsified and has a high pulling power. Ink with a low pulling power tends to be insufficiently transferred to the printing plate. Moreover, the printer must feed a larger quantity of the ink so that the ink penetrates deeper into the screen parts and the reproduction becomes heavier to avoid the formatio of insufliciently covered areas. With wet-in-wet printing, the ink pulling power also effects the acceptance of a second ink printing upon a previously effected first ink printing, and experience shows that the pulling power of the ink used for the second printing should be lower than the ink used for the first printing to obtain a satisfactory acceptance of the second ink printing. As stated before, the ink pulling power depends, among other factors, upon the degree of emulsification of the ink and hence the water-ink ratio must be particularly carefully supervised and controlled for printing operations of the kind last referred to to obtain a good and constant acceptance of the ink.

Supervision of the ink pulling power presents several problems. Any measured value of the ink pulling power is strongly affected by the thickness of the layer of ink pulling power which is to be measured, as will become more fully apparent from the hereinafter described method of measuring the pulling power of printers ink. Accordingly, measuring values of the ink pulling power can be truly compared only with ink pulling power values obtained for an ink layer of the same thickness unless the influence of the thickness of the ink layer is taken in account by suitable computations.

Basically, the ink pulling power is a function of the ratio of the supply of water and the supply of ink. Accordingly, if the feed of water exceeds the consumption of water, the ink will gradually obtain a reduced pulling power. Conversely, an ink pulling power which is too high for a constant thickness of the ink layer is indicative of the insufficient feed of water. In the practice as heretofore known, neither the ink pulling power nor the thickness of the ink layer are indicated by an instrument associated with the printing press. The printer simply accepts the aforementioned fluctuations of the quality of the printing as inherent and unavoidable with offset printing.

There is known a measuring device for measuring the ink pulling power of printer's ink as used in a printing press. However, the measuring device as known does not take in account the thickness of the ink layer and the temperature to which the ink is exposed is not held constant. Accordingly, changes in the thickness of the ink layer or in the ambient temperature will be falsely indicated as a change in the ink pulling: power. It is well known that, for example, cool air drafts in the room in which the printing press is located may cool the ink layer to such an extent that the resulting evaporation of the moistening water on the surface of the respective roller of the press manifests itself in an indication of an increase in the ink pulling power, Another disadvantage of the aforereferred to known measuring device is that it must be calibrated by applying kerosene to the respective rollers and that the indications of the device are dependent on speed. These two difficulties are due to the fact that the measuring roller of the device does not produce values which can be duplicated in the actual printing operation, since the thickness of the ink layer and the temperature are not taken in account by the devices. Furthermore, the installation and the use of the known measuring device are not practical in a printing plant.

There is also known a measuring device for measuring the thickness of the ink layer on the respective roller in the printing press, but this device does not include means for measuring the .pulling power of the ink. It merely serves to supervise the ink feed. It includes only a single measuring roller which coacts with an inker roller of the press. The measuring roller is so mounted that it is capable of yielding, against the action of a spring, in tangential direction in reference to the peripheral wall of the inker roller. The magnitude of such tangential movement is then utilized as an indication of the pulling power of the ink. However, since the absolute value of the tangential force acting upon the measuring roller and causing displacement of the same depends upon the thickness of the ink layer, the device is incapable of producing absolute values but at best can supply only values that are suitable for comparison,

The aforediscussed known measuring devices have the further disadvantage that an elastic roller and a rigid roller always coact as inker roller and measuring roller or vice versa. Accordingly, the generated tangential forces which control the obtained measured values depend very strongly upon the elasticity of the elastic roller assuming that all other conditions are alike. The elasticity of the roller is, in turn, affected by the relative velocity of the engaging surfaces, the temperature and the duration of the measuring operation so that measuring devices of this type are not capable of producing measured values which are either truly reproducible values or absolute values.

It is a broad object of the present invention to provide a novel and improved device for supervising the pulling power of the ink on an inker of a printing press, which device is capable of producing reproducible or absolute values due to being sensitive to the aforediscussed variables and responding in its indications or control actions to such variables.

It is also an object of the invention to provide a novel and improved supervisory device of the general kind above referred to which can be conveniently calibrated and the servicing of which is very simple.

A further object of the invention is to provide a novel and improved device of the general kind above referred to which greatly facilitates the production of printings having a substantially constant quality. The device of the invention indicates to the printer the pulling power of the ink for a given thickness of the layer so that the printer can compare the indicated values with values which he has obtained on the basis of experience for ink layers having the same thickness. Such possibility of comparison is particularly advantageous when a new printing run is to be started for which the same ink and the same paper are to be used.

The aforementioned objects, features and advantages and other objects, features and advantages which will be pointed out hereinafter are obtained by providing two freely rotatable measuring rollers engageable with an ink bearing roller, One of the two measuring rollers is mounted so that it is radially displaceable in reference to the rotational axis of the inker roller and the other measuring roller is so mounted that it can perform tangential movements in reference to the peripheral wall of the inker roller. The radial and the tangential movements of the two rollers are independently measured and utilized or compared by suitable comparing means. As it is evident, the radial displacement of the one measuring roller is a function of the thickness of the ink layer and the tangential displacement of the other measuring roller is a function of the pulling power of the ink.

The two measuring rollers are preferably so arranged that they act upon the same axially extended circumferential strip on the peripheral wall of the inker roller, but in circumferentially spaced relationship. The width of the measuring rollers is such that it constitutes only a small fraction of the total width of the inker roller. Accordingly, the tangential forces as caused by the pulling or link separation power are, for all practical purposes,

measured at the same peripheral area at which the second measuring roller probes the thickness of the ink layer by the radial position of the roller. Such sensing of a very limited surface area is of particular importance if the pattern to be printed involves the use of ink layers which are of different thickness across the width of the inker roller.

The invention also provides means for maintaining the temperature of the inker roller substantially constant. As stated before, the consistency of the ink is strongly affected by the temperature thereof. The ink temperature is influenced not only by the room temperature but also by the length of time for which the machine is in operation. A supervision of the temperature of the inker roller is essential to obtain truly accurate measured values. Such measured values which take in account the thickness of the ink layer provides a printer with valuable information as to the ink to be used. For instance, the measured values indicate to the printer the extent to which the ink should be diluted while and when the press is still cold. When he starts a fresh run of the same job, he can immediately set the printing conditions for optimal performance on the basis of the measured values obtained with the preceding run. He can also conveniently adjust multi-color printing presses for the correct sequence of the pulling power of the ink to be used. As it is now evident, the measured values can be comparatively used only if they are applied to conditions of equal temperature and equal thickness of the ink layer.

In many instances, the surface of the inker roller is rigid, but if the ink conditions on an elastic inker roller are to be supervised, the invention provides a rigid auxiliary inker roller coacting with the two measuring rollers which also have a rigid surface. This auxiliary roller has the width of the measuring rollers and engages the elastic inker roller. As it is evident from the previous description, such auxiliary inker roller with a hard surface provides the conditions required for obtaining accurate measuring results.

The mounting of the two measuring rollers, according to the invention, may be so arranged that it permits limited departures from the parallel orientation of the rotational axes of the measuring and the inker rollers. This has the advantage that localized unevennesses in the peripheral wall of the rigid inker roller and tolerances in the bearings for the measuring rollers are automatically compensated for so that the measuring rollers abut the inker roller along substantially their entire widths as it is desired.

To eliminate the effect of the circumferential grooves, scratches, etc. in the peripheral wall surfaces of the rollers, as may develop during prolonged operation of the device and the press, upon the indications and control functions of the measuring device, means may be provided to impart to the measuring rollers a limited axial reciprocating movement. Even a slight axial movement is generally sufficient to eliminate the effect of any operationally occuring flaws in the surfaces of the rollers.

The aforementioned comparing means for comparing the radial and tangential displacements, respectively, of the measuring rollers may comprise an analog computer of conventional design which is so programmed that it combines the values measured by the two measuring rollers and produces a single value incorporating all magnitudes fed to it.

In the accompanying drawing, several preferred embodiments of the invention are shown by way of illustration and not by way of limitation.

In the drawing:

FIG. 1 is a diagrammatic elevational side view of a supervisory device according to the invention in coaction with an inker roller of a printing press;

FIG. 2 is a left hand end view of FIG. 1;

FIG. 3 is a right hand end view of FIG. 1;

FIG. 4 is an elevational side view similar to FIG. 1, but showing a modification of the supervisory device;

FIG. 5 is a right hand end view of FIG. 4;

FIG. 6 is an elevational side view of another modification of the supervisory device;

FIG. 7 is a left hand end view of FIG. 6; and

FIG. 8 is a block diagram of comparing means for the device.

Referring now to the figures in detail, the measuring or supervisory device as exemplified in FIGS. 1, 2 and 3 is shown in coaction with a roller 1 of an inker of a printing press. The roller, such as a rubbing roller, has a nonelastic or rigid peripheral surface.

The measuring device comprises two measuring rollers 2 and 3 which have a rigid peripheral surface and may be metal rollers. The rollers are both supported by a holder assembly 4 which, in turn, is supported on a cross bar 5 which may be visualized as a part of the frame structure of the press. The holder assembly is lengthwise slidable on bar 5 and may be secured in any selected lengthwise position in reference to roller 1 by tightening clamping bolts 6. As it is clearly shown in FIG. 1, the width of measuring rollers 2 and 3 is a fraction of the total width of roller 1.

Measuring roller 2 is journalled, preferably, by means of suitable roller bearings in two brackets 7, each of which is coupled by a flexible member, such as a flat spring '8, to a respective arm 9. The elastic mounting for roller 2, as just described, is biased to urge rollers 2 into engagement with the peripheral wall of inker roller 1.

Inker roller 1 should be visualized as being coated with a layer of printers ink, the thickness of which is to be continuously supervised by the measuring device of the invention and more specifically, by the measuring roller 2 thereof. As it is evident, roller 2 is slightly movable in radial direction in reference to the rotational axis of inker roller 1 due to the provision of flexible springs 8. Accordingly, the radial position of roller :1 is continuously a function of the thickness of the inker layer on roller 1. Suitable detecting means shown as electric strain gauges 101 and 102 are secured to the two flat springs 8 as it is shown in FIGS. 2 and 3.

The two strain gauges may be visualized as being connected in a conventional and well known indicating or control circuit controlled by the flexing of the strain gauges. As it is apparent from the previous description, the flexing of the strain gauges is controlled by the radial position of measuring roller 2 which, in turn, is controlled by the thickness of the ink layer of roller 1. The circuits may be visualized as supplying suitable indications or initiating control functions. Circuits of this kind are well known in the art and do not constitute part of the invention.

Measuring roller 3 is similarly supported by a bracket or frame 11, which is coupled by flexible members 12, such as flat springs, to arms 13. The frame structure 11 includes elongated slots 14 which coact with brackets 7 to permit the aforedescribed radial displacement of measuring roller 2, as it is clearly shown in FIGS. 2 and 3.

Arms 9 and 13 for the two measuring rollers are joined to or constitute part of holder assembly 4.

As it is evident, inker roller 1 rotates when the press is in operation and due to such rotation, a tangential force is exerted upon roller 3, the peripheral wall of which is biased by springs '12 into engagement with the ink layer on roller 1, thereby causing a corresponding substantially tangential displacement of roller 3. This displacement manifests itself in a corresponding flexing of springs 12. This flexing is measured by suitable measuring means shown as electric strain gauges 103 and 104. These strain gauges may also be visualized as being included in a suitable indicating or control circuit. The indications or control functions of this circuit constitutes a function of the tangential displacement of roller 3 which, in turn, is a function of the pulling power of the ink layer thereon and also of the rotational speed of roller 1. To prevent oscillations of the support for roller 3 which may falsify the signals produced by the strain gauges, a damping means 16 of conventional design may be interposed between frame 17 and the holder assembly 4 by means of a rigid arm 15.

As it is evident from the previous description, the mounting for the two measuring rollers may be widely modified within the scope of the invention. It is only essential that springy members, such as flat springs 8 and 12, are provided which are sensitive to the radial and the tangential position, respectively, of the rollers. The positions of the measuring rollers supply accurate indications of the pulling power of the ink layer and of the thickness of the layer and the rotational speed thereof in reference to the measuring rollers. As it is also evident, the springs 8 and 12 automatically compensate for minor flaws in the surfaces of the coacting rollers and for minor misalignments of the rollers.

FIGS. 4 and 5 show a measuring device which is similar in principle to the measuring device as described in connection with FIGS. 1, 2 and 3. While in the measuring device of the previously described figures, the measuring rollers 2 and 3 are disposed in axially spaced relationship so that they will detect the condition of the ink layer on different circumferential areas of roller 1, the device according to FIGS. 4 and 5 comprises two measuring rollers 18 and 19 which are disposed. in aligned and circumferentially spaced relationship in reference to an ink layer on an inker roller 17. Accordingly, measuring rollers 18 and 19 detect the condition of the ink layer on the same circumferential area of inker roller 1'7. The widths of the two measuring rollers are again a fraction of the Width of inker roller 17.

The mounting and suspension of roller 18, that is, of the roller capable of being tangentially displaced, are the same as described for roller 3 in connection with FIGS. 1, 2 and 3. Accordingly, the same reference numerals are used to designate corresponding parts.

The second measuring roller 19, that is, the roller capable of radial displacement, is supported by a frame structure 21 which, in turn, is coupled by flexible members 22, such as flat springs, to a support structure 24. Support structure 24 is secured to or constitutes part of bushings or sleeves 23 of a holder assembly 20. The entire holder assembly is again slidable on a cross bar, such as cross bar 5, and may be secured thereon in any selected lengthwise position as has been described in connection with FIGS. 1, 2 and 3. The angular position of support structure 24' may be adjusted by a set screw 25. A loaded coil spring 26 urges the structure 24 and with it the entire support for roller 19 into engagement with fixed arm 15. The set screw 25 is so adjusted that roller I19 will engage the ink layer on inker roller 17.

As it is evident from the previous description, varia tions in the thickness of the ink layer will cause a corresponding radial displacement of roller 19. Such displacement is again detected by strain gauges 101 and 102.

The strain gauges 101 through 104 should be visualized as being included in indicating or control circuits similar to the one described in connection with FIGS. 1, 2 and 3.

FIGS.6 and 7 show a measuring device designed for accurately supervising the pulling power of the ink layer on an inker roller 17a which is covered with an elastic lining 41. As has been initially explained, the accuracy of the indications obtainable with the measuring device according to the invention is affected by the hardness of the coacting peripheral wall surfaces of the rollers. To obtain accurate indications in spite of the elastic and thus soft lining 41 on the inker roller, an auxiliary inker roller 17b with a hard peripheral surface is interposed between measuring rollers 18 and 19 and the ink layer on the elastic lining 41 of inker roller 17a.

As has also been previously explained in the specifica tion, the accuracy of the indications obtainable with the measuring device according to the invention is further affected by the temperature of the ink layer. To provide a substantially constant temperature condition, a suitable heating means 40 is provided within auxiliary roller 17b.

This heating means is shown as electrical heating elements connected via a temperature sensitive means, such as a thermostat 39 of conventional design, to slip rings 38 and 38a. These slip rings should be visualized as being connected to a suitable source of current and supply power to heating elements 40 under the control of thermostat 39.

Tangentially displaceable measuring roller 18 and radially displaceable measuring roller 19 are supported as described in connection with the previous figures and, accordingly, the same reference numerals are used to designate functionally corresponding components. The tangential and radial displacements of measuring rollers 18 and 19 are again detected by electric strain gauges 101 through 104, strain gauge 104 should be visualized as being mounted on the second branch of bracket 111 which is not visible in FIG. or FIG. 6.

A support frame 24a is secured to or integral with a holder assembly 30 which is lengthwise slidable on cross bar 5 and a second cross bar 31. The second cross bar guides the holder assembly parallel to the rotational axes of measuring rollers 17a and 17b. Both cross bars 5 and 31 and also rollers 17a and 17b are supported in a wall 28 which may be visualized as part of the frame structure of the printing press.

A diagrammatically indicated gearing 33 is slidably supported on bars 5 and 31. The gearing may be secured in any selected lengthwise position by a set screw 34 and is driven by a motor 32. The gearing drives a disc 35 which is eccentrically coupled by a lever 36 and a pivot pin 37a to a lug 37 on holder assembly 30. As it is evident, rotation of disc 35 will cause a corresponding reciprocating movement of assembly 30 and thus of measuring rollers 18 and 19. Such reciprocating displacements of the measuring rollers have the advantage that the effect of any flaws, such as grooves or depressions that may be present in the circumferential area of the ink layers detected by the measuring rollers, will be greatly reduced.

As has been previously explained, the signals produced by the strain gauges may be utilized in a well known and conventional manner to indicate the radial positions and the tangential positions, respectively, of the measuring rollers. The indications thus obtained are available to the press operator as a guidance for appropriate corrective steps to be taken.

However, it is also possible, and in some instances, preferable, to combine the signals obtained by the strain gauges or other detecting means associated with the two measuring rollers.

FIG. 8 shows diagrammatically a comparing means for comparing all the signals obtained from the strain gauges. Strain gauges 101 and 102 are connected to input terminals 105 through 108 of a suitable computer 44, such as an analog computer. Similarly, strain gauges 103 and 104 are connected to input terminals 109 through 112 of the computer. The computer will compare the signals in a well understood manner which does not constitute part of the present application. It is connected to a supply current indicated at 43 and operates a supervisory means 42. The supervisory means may be an indicating instrument, such as an audible or visual instrument. It may also be a control device which automatically initiates suitablecorrective steps. Arrangements of this kind are well known and do not constitute part of this application.

While the invention has been described in detail with respect to certain now preferred examples and embodiments of the invention, it will be understood by those skilled in the art, after understanding the invention, that various changes and modifications may be made without departing from the spirit and scope of the invention, and it is intended, therefore, to cover all such changes and modifications in the appended claims.

What is claimed is:

1. A device for supervising the pulling power of a layer of ink on a roller of a printing press, said device comprising: a roller bearing a layer of ink; a first freely rotatable measuring roller; a first mounting means supporting said measuring roller radially displaceable in reference to the rotational axis of the roller bearing the ink layer to be supervised; first detecting means for detecting changes in the radial position of said measuring roller as caused by changes in the thickness of said ink layer and generating signals corresponding to the detected position changes; a second freely rotatable measuring roller, a second mounting means supporting said second measuring roller tangentially displaceable with reference to the rotational axis of the roller bearing the ink layer; second detecting means for detecting changes in the tangential position of said second measuring roller as caused by changes in the pulling power of said ink layer and generating signals corresponding to the detected position changes; means responsive to the signals of said changes in the positions of the measuring rollers for computing the pulling power of said ink layer, said measuring rollers having rigid peripheral wall surfaces and the ink layer bearing roller having an elastic peripheral wall surface; and an auxiliary inker roller having a rigid peripheral wall surface, said auxiliary roller being interposed between said measuring rollers and the ink layer bearing roller in engagement with the wall surfaces of the measuring rollers and the wall surface of the roller bearing the ink layer.

2. A device according to claim 1 and comprising heating means within said auxiliary roller for maintaining the temperature of the ink layer on said ink bearing roller substantially constant.

3. A device for supervising the pulling power of a layer of ink on a roller of a printing press, said device comprisnig: a roller bearing a layer of ink; a first freely rotatable measuring roller; a first mounting means supporting said measuring roller radially displaceable in deference to the rotational axis of the roller bearing the ink layer to be supervised; first detecting means for detecting changes in the radial position of said measuring roller as caused by changes in the thickness of said ink layer and generating signals corresponding to the detected position changes; a second freely rotatable measuring roller, a second mounting means supporting said second measuring roller tangentially displaceable in reference to the rotational axis of the roller bearing the ink layer; second detecting means for detecting changes in the tangential position of said second measuring roller as caused by changes in the pulling power of said ink layer and generating signals corresponding to the detected position changes; means responsive to the signals of said changes in the positions of said measuring rollers for computing the pulling power of said ink layer; support means supporting said first and second mounting means displaceable parallel to the rotational axes of the measuring rollers; and reciprocatory drive means for reciprocating said support means.

4. A device according to claim 3, wherein said first and second mounting means support said measuring rollers m a clrcumferentially aligned and spaced apart relationship with reference to said ink layer bearing roller, the widths of the measuring rollers being less than the width of the roller bearing the ink layer.

5. The device according to claim 3, wherein each of said mounting means comprises a flexible member flexed in response to a change in the position of the respective measuring roller, and each of said detecting means comprises an electric strain gauge means secured to the respective flexible member to particpiate in the flexing thereof, the flexings of said strain gauge means being indicative of the radial and tangential position respectively of the measuring rollers.

References Cited UNITED STATES PATENTS 2,224,728 12/1940 Gulliken 33-147 X 2,503,720 4/ 1950 Gieseke 33-147 X (Other references on following page) 9 UNITED STATES PATENTS Frommer 33-447 X Brown 33-147 X Gruebel 73-150 Jorgensen 73150 X Beyeler 33-172 10 LOUIS R. PRINCE, Primary Examiner.

M. J. NOLTON, Assistant Examiner.

us. 01. X.R. 5 73 1s9; 33-472 

